#define _CRT_SECURE_NO_WARNINGS 1
#include <stdio.h>
#include <math.h>

int main()
{
	int a, b, c;
	scanf("%d%d%d", &a, &b, &c);

	double x0 = 1;
	double x1 = 0;
	while (1)
	{
		double fx = a * pow(x0, 5) + b * pow(x0, 2) + c;
		double f_x = 5 * a * pow(x0, 4) + 2 * b * x0;

		x1 = x0 - fx / f_x;
		if (fabs(x1 - x0) < 1e-5)
		{
			printf("%.2f", x1);
			break;
		}
		x0 = x1;
	}


	return 0;
}